[NTG-context] Standalone MetaPost Graphics from ConTeXt

Is there a way to output several MetaPost PDF graphics from a single ConTeXt source file. For example, \startMPpage draw fullcircle scaled 72; \stopMPpage \startMPpage draw unitsquare scaled 72; \stopMPpage and have a separate output PDF generated for each MPpage? It seems that this ConTeXt code generates a single PDF which contains only the first graphic. I would like to have either 1) two separate PDF's with each containing their own graphic 2) a single two page PDF where each page corresponds to the appropriate graphic. Of course, the "holy grail" would be to be able to "compile" a MetaPost source file with ConTeXt. Troy Henderson